As semiconductor devices continue to be scaled to ever smaller dimensions, the properties of the device materials begin to provide constraints and new challenges in achieving the projected benefits of scaling. The introduction of ferroelectric films and devices has not slowed the scaling trend. For example, over the past decade, ferroelectric random access memory (FRAM) has emerged as a viable non-volatile memory for applications requiring low power, fast read/write access time, and high cycling endurance.
However, scaling requires decreased ferroelectric thin-film thickness, which may result in reduced polarization of the ferroelectric film. In FRAM applications, reduced polarization can result in reduced FRAM signal margin, which is a key metric for reliable operation of the FRAM, because the FRAM signal margin is directly related to the amount of switched polarization (Psw) in the capacitor formed using the ferroelectric film.